Waterproof asbestos sheet and method of producing same



aimed Jul 17, 1934 umrso' STATES.

LQBMISZ WATERPROOF ASBESTOS SHEET ANIII) DIETHOD 0F PRODUCING SAME Izador J. Novak, Bridgeport, Com, assignor to Baybestos-Manhattamjna, Bridl l (301111., a corporation of New Jersey 1 No Drawing. Application December 19, 1931. Serial No. 582,184

An object of this invention is to produce a waterproof, fireproof'sheet, comprising asbestos as the base fiber, adapted for many uses such, for

instance, as a gasket material where the sheet may be supported by a metallic backing; as an insulating board or the like.

The steps involved in the preparation of a waterproof,,fireproof asbestos sheet according tothe present invention are essentially, first, to select an extremely waterproof substance as a sizing material, and second, to hold the combustible material in the sheet to a .very low percentage,

, preferably below 15%. Further, inasmuch as an asbestos sheet'containing lowpercentages of sizing material may be relatively soft and flimsy, it is desirable to produce a stiffening binder of such a nature in combination with the waterproofing agent as to retain as much as possible the waterproof ualities.

In one embodiment ofpreparing a sheet according to the invention, 1 may mix in a beater engine the following ingredients:

Pounds Asbestos fiber, approximately 2, 000 oleic acid (emulsified) approximatelyf--- 60 Formaldehyde-treated glue 'gel' approximately 40 These ingredients are thoroughly mixed and about 100 pounds of aluminum sulfate or other precipitating agent in water solution may be then added and the beating continued until all of the precipitated metallic soap and glue have been thoroughly smoothed out. The stock is then run off on a suitable paper machine, either of the wet machine "type which produces individual sheets, or of the continuous type to produce continuous lengths. Instead of aluminum sulphate, I may use any other precipitating agent such, for instance, as sulphuric acid, ironsulplidjte, magnesium sulphate, or acid metallic sa s. a

Any' desirable method of precipitating the size on the fibers may be used within the contemplatipn of this invention.

I One method of preparing the emulsified oleic acid size is to heat approximately 300 pounds of water to about 125 F., dissolve completely therein about three pounds of technical caustic soda or similar alkali, making a solution of les than 1% alkali, and slowly add, with stirring, about 30 pounds of oleic acid or similar saponifiable fatty acid. This is then thoroughly agitated, preferably with live steam, and when the temperature has been increased to about 175 F. the product will be a thin cream-colored liquid equivalent to about 10% oleic acid concentration. Mechanical agitation may be substituted for steam agitation.

The glue gel may be made as follows:

@laims. (C11. 91-68) About 20 pounds of glue may be dissolved in approximately 350 pounds of water at about 160 F. with stirring. Then about 1 pound of 40% formaldehyde solution may be added thereto with stirring. The mixture may then be allowed to cool, whereupon a soft gel is produced, which may bebroken up and added to the beater. The use ties are desirable; and as an insulating material. The stiffness and waterproof qualities of the sheet may be varied by varying the proportions.

of these ingredients. For instance, if it is desired a to make a less stiff sheet than would be made by the above proportions of ingredients, the proportion of glue might be decreased. Likewise, if it is desired to increase the waterproofing properties of the structure, additional size maybe used.

Other fatty acids such as those of vegetable or animal oils may be used in place of oleic acid, and other stiffening agents such as alkaline casein, alkaline shellac, alkaline phenolic resins, and the like, preferably in soft gel form so as to secure maximum efficiency, may be used in place of the formaldehyde-treated glue.

If desired, small percentages of vegetable fiber, less than 10% relative to the asbestos fiber, may

be mixed with the asbestos for improving the' strength or paper making qualities of the composition. 7

As far as I am aware, it is new to produce an asbestos base containing a fatty acid size to an organic stiffening agent wherein the proportion of combustible material is lower than 15%.

I claim as my invention:

1. A fibrous base comprising asbestos containing a waterproofing fatty acid size and an organic stiffening agent uniformly distributed throughout the thickness of the base wherein the proportion of combustible material is lower than 15%, said agent being capable of .substantially retaining the waterproof qualities of the base.

2. A waterproof, fireproof fibrous base comprising asbestos containing a waterproofing. fatty acid size and an organic stiffening agent comprising formaldehyde treated glue gel.

3. A waterproof, fireproof fibrous base comprising asbestos containing a waterproofing fatty' acid size and an organic stiffening agent comprising formaldehyde treated glue gel, wherein the proportion of combustible material is lower than 15%.

IZADOR J. NOVAK. 

